1. Field of the Invention
This invention relates to a bend resistant cable, such as a cable for an electromechanical brake (EMB) of vehicles, robots, or an unsprung mass of vehicles etc, used in an environment requiring a bend resistance and a tensile strength. In particular, this invention relates to a bend resistant cable whose internal conductor structure is formed by stranding multiple child stranded conductors.
2. Description of the Related Art
In recent years, according as various automobile devices are electrified, various automobile cables such as EMB cables have been used. The automobile cables are used under a severe condition that requires characteristics such as a bend resistance and a tensile strength. For example, the EMB cables need to have a bend resistance and a tensile strength since they are frequently subject to vibration due to the operation (driving) of a suspension device.
As an automobile cable used in the environment requiring the bend resistance and the tensile strength, a bend resistant cable 40 as shown in FIG. 4 has been proposed.
The bend resistant cable 40 is constructed such that an insulation layer 43, a reinforcing braided layer 44, and a jacket 45 are sequentially formed on the periphery of a stranded wire 42 that is formed by stranding multiple child stranded conductors 41 each having multiple strands. The bend resistance and the tensile strength can be enhanced by the reinforcing braided layer 44 under the jacket 45.
In this cable with the child stranded conductors stranded, the child stranded conductors composing the stranded wire contact with each other. When it is bent, stress is applied to contact portions therebetween. Thus, the cable may be broken finally by receiving the stress repeatedly.
In order to solve the above problem, JP-A-2004-87436 discloses an aluminum cable for automobiles that a child stranded conductor at the center of a stranded wire has a smaller diameter than that of the other child stranded conductors, and JP-A-2003-303517 discloses an aluminum cable for automobiles that at least one of the child stranded conductors composing the stranded wire is coated with lubricant.